Kentucky bluegrass and bermudagrass rooting response to humic fertilizers during greenhouse establishment

Abstract

Greenhouse research was conducted to examine effects of adding humic products to fertilizers on turfgrass. The objective of this study was to determine if the addition of humic products to fertilizers will increase turfgrass root and shoot morphological parameters. Kentucky bluegrass (KBG; Poa pratensis L.) and bermudagrass [Cynodon dactylon (L.) Pers.] were established in sand-filled tubes. Treatments included synthetic fertilizer with black gypsum (22N-0P-3.3K, 30% gypsum and 4.7% humic acid), polymer-coated humic-coated urea (PCHCU; 2% humic acid), urea with humic dispersing granules (HDG; 70% humic acid), starter fertilizer (18N-10.5P-10K) with HDG, starter fertilizer, stabilized nitrogen, urea, and a control group. Fertilizers were applied at 48.8 kg N ha −1 and HDG was applied at 44.4 kg ha −1. Starter fertilizer and starter fertilizer with HDG increased KBG total root length (105 and 112%), root biomass (232 and 244%), and shoot biomass (205 and 204%) compared with urea. In KBG, PCHCU and urea with HDG increased total root length (37 and 20%) compared with urea. In bermudagrass, starter fertilizer and starter fertilizer with HDG increased total root length (241 and 248%), root biomass (672 and 707%), and shoot biomass (821 and 808%) relative to urea. Besides treatments with starter fertilizer, no treatments were different from urea for bermudagrass. These results suggest that starter fertilizer application is critical to turfgrass rooting at establishment. Adding humic products to the starter fertilizer did not increase rooting. In the absence of a starter fertilizer, PCHCU and urea with HDG improved KBG total root length compared with urea.

Evaluation of humic fertilizers on a sand‐based creeping bentgrass putting green

“…Threshold settings of hue (71–176), saturation (10–100), and brightness (0–100) were used for DIA. Clippings were collected monthly from one mowing event using a reel‐mower, dried at 80 °C for 3 d, and weighed (Lindsey et al., 2020). Sand was removed from clippings before being weighed.…”

Evaluation of Humic Fertilizers Applied at Full and Reduced Nitrogen Rates on Kentucky Bluegrass Quality and Soil Health

“…Festuca arundinacea Scherb.) 57% root mass, 78% α-tocopherol, 39% ascorbic acid [30] Tall Fescue 9% photochemical efficiency, 5% heat tolerance, 21% root strength [37] Perennial ryegrass (Lolium perenne L.) 8% total chlorophyll, 9% root length [38] Perennial ryegrass 4% turfgrass quality, 10% shoot length [39] Kentucky bluegrass (Poa pratensis L.) 19% shoot mass, 60% root mass, 38% α-tocopherol, 25% ascorbic acid [40] Kentucky bluegrass 14% photochemical efficiency, 36% heat tolerance, 22% root strength [41] Kentucky bluegrass 54% root mass [42] Kentucky bluegrass 21% turfgrass quality, 16% normalized vegetation index (NDVI), 11% microbial biomass carbon [43] Kentucky bluegrass 87% total root length, 91% root surface area, 94% root volume [22] Bermudagrass (Cynodon dactylon (L.) Pers.) 87% longest root [22] 2.…”

“…First, we hypothesize that adding humic products incorporated with N fertilizer will enhance turfgrass efficiency, thus allowing for lower N rates to maintain similar quality. This may be due to enhanced root growth, and/or microbial stimulation with efficient cycling of N with added C source from humic products [22][23][24]. Second, we hypothesize that this added C source with humic-treated N fertilizer products will increase microbial biomass, labile supply of C and N, and general activity.…”

Evaluation of Humic Fertilizers on Kentucky Bluegrass Subjected to Simulated Traffic

“…[33,40]. Kentucky bluegrass heat injury recovery or tolerance, root mass, root strength, root growth and turf quality was enhanced by application of humic substances [41][42][43][44][45]. Humic substances applied to perennial ryegrass (Lolium perenne L.) improved root length and surface area, root architecture, and visual quality [46,47].…”